1a Ali has 8 CDs that he is going to give away He lets his b

1a. Ali has 8 CDs that he is going to give away. He lets his best friend choose 2 of the 8 CDs. How many different groups of 2 CDs are possible?

1b. Omar has been given a list of 5 bands and asked to place a vote. His vote must have the names of his favorite, second favorite, and third favorite bands from the list. How many different votes are possible?

Solution

a) Total 8 CDs

Friend selects 2 CDs

Possible combination : 8C2 = 8!/2!6! = 56/2 = 28

b)  There are five possibilities for the favorite. You have picked a band as your favorite, that only leaves four different bands as your possible second-favorite, there are four possibilities for your second place

So, possible different votes = 5*4*3 = 60